She was admitted to King's College Hospital in London at the weekend. A spokeswoman described her condition as "criti-cal but stable".

It remained unclear whether her illness was a recurrence of the brain tumour.

The ex-MP for Redcar quit the Commons at the 2001 election after 14 years.

She frequently returned to Coventry where her mother lived and attended her old school for reunions.

In March she was in Coventry as a special guest for the launch of the Women's Festival.

Two years ago she was back at Coundon Court, which she left in the late 60s, to meet her old pals and recalled her fondness for her teachers.

She said the school provided a "privileged education" and springboard to success for many at the reunion.

"The teachers were wonderful," said Mo, as she stood with classmates in the Old School House.

"I realised when I went on to university that I'd been given an excellent foundation in history, English, geography, maths.

"I remember it was here where we let the fire alarm off just to test the system. I was head girl but I wasn't very ruly - I was always pushing the rules out just to test them. At the time I was just having good fun."

She was made Northern Ireland Secretary when Labour swept to power in 1997 and quickly made a name for herself as a down-to-earth and often too honest politician.

Ms Mowlam won universal admiration for her perseverance in working towards the Good Friday peace agreement the following year.

It was magnified by the fact that she was recovering from treatment for the brain tumour at the time.

Renowned for her light-hearted disregard of formality, kicking off her shoes and chewing gum at meetings, she is reputed to have removed her wig to break the tension during key meetings.